The required parameters depend on the transaction type. Check the proper parameters in Klaytn Docs.
params: [{
"typeInt": 18,
"from": "0xcd01b2b44584fb143824c1ea0231bebaea826b9d",
"to": "0x44711E89b0c23845b5B2ed9D3716BA42b8a3e075",
"gas": "0x4a380",
"gasPrice": "0x5d21dba00",
"nonce": "0x2c",
"value": "0xf4",
"input": "0xb3f98adc0000000000000000000000000000000000000000000000000000000000000001",
"feePayer": "0xcd01b2b44584fb143824c1ea0231bebaea826b9d",
"feeRatio": 30,
"signatures": [{
"V": "0x4e43",
"R": "0xd3ff5ca7bdd0120d79e8aa875593d05022fe74ce2b7a0594218d53c0fdca7fa9",
"S": "0x2c100e69d2455afc9393e017514063da18b18db6f7e811d0aeaf6002515b58ef"
}]
}]
// Request
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"klay_sendTransactionAsFeePayer","params":[{see above}],"id":1}' http://klaytn.blockpi.network/v1/rpc/your-api-key
// Result
{
"jsonrpc": "2.0","id":1,
"result": "0x77ec2d910d0b96585373e2d6508f2b2d8c2af7d0060d2012e1cb2f0ee9d74830"
}